Abstract:Effect of annealing and solution treatment prior to cryorolling on the formation of initial structure influencing microstructure formation from nano to micron scale and resultant mechanical and corrosion properties in Al 1100 alloy has been studied in detail. Before subjecting to 50% cryorolling, samples were pre-annealed at 250 °C for 2 h and pre-solution treated at 540 °C for 1 h. X-ray diffraction and HRTEM techniques were used to understand the crystallite size, lattice strain and dislocation configuration in the processed alloy. The results indicate that the pre-annealed sample has the highest grain aspect ratio (4.43), the smallest crystallite size (37.53 nm), the highest lattice strain (9.12×10^-3) and the highest dislocation density (45.16×10¹³ m^-2) among the tested sample. The pre-annealed sample shows a significant improvement of 43.44%, 24.64% and 20.33% in hardness, ultimate tensile strength and yield strength. Both pre-annealed and pre-solution treated samples show improved corrosion resistance when compared to cryorolled samples without any pre-treatment, with the pre-annealed sample showing the best corrosion resistance.

Key words: cryorolling; Al 1100 alloy; pre-heat treatment; nanostructure; ultrafine-grain; mechanical properties; corrosion resistance